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MDEV-7950 Item_func::type() takes 0.26% in OLTP RO

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Step #3: Splitting the function check_equality() into a method in Item.
Implementing Item::check_equality() and Item_func_eq::check_equality().
Implement Item_func_eq::build_equal_items() in addition to
Item_func::build_equal_items() and moving the call for check_equality()
from Item_func::build_equal_items() to Item_func_eq::build_equal_items().
This commit is contained in:
Alexander Barkov
2015-05-05 01:09:47 +04:00
parent 9090c3efca
commit 2fe4d0e6cd
3 changed files with 38 additions and 24 deletions
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10
sql/item.h
View File

@ -1133,6 +1133,16 @@ public:
update_used_tables();
return this;
}
/*
Checks whether the item is:
- a simple equality (field=field_item or field=constant_item), or
- a row equality
and form multiple equality predicates.
*/
virtual bool check_equality(THD *thd, COND_EQUAL *cond, List<Item> *eq_list)
{
return false;
}
virtual void split_sum_func(THD *thd, Item **ref_pointer_array,
List<Item> &fields) {}
/* Called for items that really have to be split */

3
sql/item_cmpfunc.h
View File

@ -562,6 +562,9 @@ public:
cond_result eq_cmp_result() const { return COND_TRUE; }
const char *func_name() const { return "="; }
Item *negated_item();
COND *build_equal_items(THD *thd, COND_EQUAL *inherited,
bool link_item_fields);
bool check_equality(THD *thd, COND_EQUAL *cond, List<Item> *eq_list);
/*
- If this equality is created from the subquery's IN-equality:
number of the item it was created from, e.g. for

27
sql/sql_select.cc
View File

@ -12685,14 +12685,11 @@ static bool check_row_equality(THD *thd, Item *left_row, Item_row *right_row,
or, if the procedure fails by a fatal error.
*/
static bool check_equality(THD *thd, Item *item, COND_EQUAL *cond_equal,
bool Item_func_eq::check_equality(THD *thd, COND_EQUAL *cond_equal,
List<Item> *eq_list)
{
if (item->type() == Item::FUNC_ITEM &&
((Item_func*) item)->functype() == Item_func::EQ_FUNC)
{
Item *left_item= ((Item_func*) item)->arguments()[0];
Item *right_item= ((Item_func*) item)->arguments()[1];
Item *left_item= arguments()[0];
Item *right_item= arguments()[1];
if (left_item->type() == Item::ROW_ITEM &&
right_item->type() == Item::ROW_ITEM)
@ -12702,10 +12699,7 @@ static bool check_equality(THD *thd, Item *item, COND_EQUAL *cond_equal,
(Item_row *) right_item,
cond_equal, eq_list);
}
else
return check_simple_equality(left_item, right_item, item, cond_equal);
}
return FALSE;
return check_simple_equality(left_item, right_item, this, cond_equal);
}
@ -12804,7 +12798,7 @@ COND *Item_cond_and::build_equal_items(THD *thd,
structure here because it's restored before each
re-execution of any prepared statement/stored procedure.
*/
if (check_equality(thd, item, &cond_equal, &eq_list))
if (item->check_equality(thd, &cond_equal, &eq_list))
li.remove();
}
@ -12893,7 +12887,7 @@ COND *Item_cond::build_equal_items(THD *thd,
}
COND *Item_func::build_equal_items(THD *thd,
COND *Item_func_eq::build_equal_items(THD *thd,
COND_EQUAL *inherited,
bool link_item_fields)
{
@ -12910,7 +12904,7 @@ COND *Item_func::build_equal_items(THD *thd,
for WHERE a=b AND c=d AND (b=c OR d=5)
b=c is replaced by =(a,b,c,d).
*/
if (check_equality(thd, this, &cond_equal, &eq_list))
if (Item_func_eq::check_equality(thd, &cond_equal, &eq_list))
{
Item_equal *item_equal;
int n= cond_equal.current_level.elements + eq_list.elements;
@ -12955,6 +12949,13 @@ COND *Item_func::build_equal_items(THD *thd,
return and_cond;
}
}
return Item_func::build_equal_items(thd, inherited, link_item_fields);
}
COND *Item_func::build_equal_items(THD *thd, COND_EQUAL *inherited,
bool link_item_fields)
{
/*
For each field reference in cond, not from equal item predicates,
set a pointer to the multiple equality it belongs to (if there is any)